This invention relates to enclosures of the refrigerated type and the method of their manufacture and more specifically to a frameless, insulated, monolithic storage enclosure with a door all made entirely of synthetic resinous material some of which is reinforced with fiberglass and mounted on a skid.
Applicant is unaware of any portable, refrigerated enclosure in the prior art structurally similar to that disclosed herein or constructed by applicant's novel method. Portable, refrigerated storage enclosures are well known in the art. They generally consist of a wooden framed structure having insulation inserted between the frame members in the form of sheet or ground cork, filamentary fiberglass or the like. The inside of the structure was typically covered with plywood panels and the outside with panels of sheet metal secured to the frame members. Condensation and the accumulation of moisture behind the metal covering soon caused the aforementioned insulating material to lose its thermal insulating characteristics. In addition, the collection of moisture in this insulating material results in rapid deterioration of the wooden framing and interior facing structure due to fungus, rot and corrosion. Further, as the thermal insulating characteristics of the insulation deteriorate, the cost of cooling the interior of the box increases which is particularly significant today due to the rising cost of electricity.
Attempts have been made to construct an enclosure of synthetic resin materials which are the subject of this invention. Such materials are both substantially nonpermeable to moisture and are non-hygroscopic. The tendency of these materials to collect moisture is negligible for all practical purposes. An example of such an attempt is disclosed in U.S. Pat. No. 3,003,810 wherein a truck body was constructed of panels of low density synthetic resin such as polystyrene which have a sublaminate of plywood secured to both sides thereof and this sublaminate is then covered by a high density resin material reinforced with fiberglass. Such a construction of synthetic materials while superior to the prior art wooden frame etc. construction aforedescribed, is entirely too complex and time consuming to construct to be economically feasible to produce on a large scale. The internal gluing and splining of the polystyrene panels together, the securement of the sublaminae to the polystyrene panels, the sealing of the joints of the sublaminae and the use of covering angles to wrap and seal the corners all greatly increase the labor and materials necessary to construct an insulated enclosure on a substantially large scale at an economical cost.
It is therefore the primary object of the present invention to provide a superior insulated storage enclosure and method of its manufacture.
It is another object of the present invention to provide a refrigerated enclosure which, due to the nature of the materials used and the unique manner of their assemblage, eliminates the complex subframe structure and the screws, bolts and other fasteners heretofore used to construct prior art structures of this nature yet achieves a structure of greater strength and durability.
It is a further object of the present invention to provide a refrigerated enclosure which, due to its simple construction, can be rapidly and cost effectively manufactured by unskilled labor employing the novel methods taught by the invention.
It is yet another object of the present invention to provide a refrigerated enclosure made entirely as a monolithic structure of, for example, a polyurethane core entirely encased in a layer of resinous material reinforced with fiberglass and having a door constructed in a similar manner.